Your point that “Rey overcame her low self-esteem in TLJ” and that “TRoS undermines this” is like saying that “she stopped caring about her parents in TFA just because she stopped waiting for them on Jakku and that TLJ undermines/undoes this by saying that Rey still cares about her parents.”
Just because Rey stopped waiting for her parents to return for her on Jakku in TFA, doesn’t mean she stopped caring about them entirely; in the exact same way, just because Rey seems happy at the end of TLJ, doesn’t mean she’s overcome her core belief that she is worthless (in fact, we see her happy in several scenes in the trilogy, especially BEFORE the TLJ reveal, but that doesn’t mean she ISN’T held back by this core belief).
Now, you’ll probably say the same thing about her TRoS arc, that “just because Rey defeated Palps, doesn’t mean she overcame her core belief that she is completely worthless,” but I digress. In fact, there’s a few indications she’s overcome her core belief of self-worthlessness by the end of TRoS:
-
Her pulling in the Skywalker lightsaber and grasping it at that moment alone implies she finally feels worthy, especially since this is the same lightsaber she felt unworthy of using twice, during one of her scenes with Leia and during her time on Ahch-To before Luke showed up.
-
At the end of TRoS, Rey finally feels worthy of naming herself “Skywalker” and continuing their legacy, whereas on Pasaana during that interaction with that little girl basically this happens: “What’s your name?” “Just Rey.” Note that this is before the climax on Exegol, so at this point on Pasaana, Rey is still held back by her core belief.
It’s not that Rey cared about her grandparents, it’s that the reason her Palpatine heritage is such a big deal to her, personally, is because she is related to the Sith Lord who murdered trillions; on top of that, it’s part of the reason she exiles herself onto Ahch-To until Luke pointed out that she is still valuable and can still do the right thing regardless of her heritage.
I meant that Rey was “unaffected” at the Battle of Crait in the sense that, well… there is a criticism that Rey should have been heavily affected by the parental reveal itself (warning, it’s from /r/saltierthancrait), which I disagree with since the reason she seems happy during Crait is because it means she has finally stopped caring about her parents themselves entirely.
Rey’s relationship by itself with Palpatine isn’t the point, the point is how the reveal of her Palpatine heritage affects her, and that she overcomes it when she learns from Luke that she is still valuable and can still do the right thing regardless of her heritage.
I think you should try re-watching TRoS (and by extension, TFA & TLJ), at least several times, with my interpretations in mind, in the hope that you can see as to where I am coming from regarding everything I said about Rey in this thread and the comment section.